This invention relates to a dry shaving apparatus.
A dry shaving apparatus of the type initially referred to is known from printed specification DE 33 02 610 A1. The removable frame disposed in a housing part sits by means of a flange on a housing ledge and is coupled to the housing by a positive-engagement detent device formed by projections engaging within recesses, said device acting in the two working directions of a movable cutter element.
A housing part provided for receiving and holding a removable frame may be arranged on the housing of a dry shaving apparatus either detachablyxe2x80x94see DE 33 02 610 A1xe2x80x94or so as to be fixedly connected with the housing, meaning that it forms a component part of the housingxe2x80x94see DE 44 10 543 C1, FIG. 10.
Positive couplings between a removable frame and a housing part of a dry shaving apparatus for the purpose of ensuring a vibration-free seat of the removable frame necessitate an engagement of cooperating positive-engagement elements free from relative movements, that is, clearance-free positive engagement. While clearance-free positive engagement is obtainable at increased manufacturing expense, it is nevertheless susceptible to wear over time due to attrition taking place during use or deformation of cooperating positive-engagement elements, thereby precluding the desired effect to reliably prevent vibration of the removable frame equipped with at least one cutter element.
From DE 196 32 333 C1 a dry shaving apparatus of the type initially referred to is known in which a non wearing seat of the removable frame in a housing part is reliably ensured, however in this known dry shaving apparatus provision is made for additional devices, such as movably mounted pressure elements in the housing which are acted upon by spring elements and urge the removable frame against a stop provided on the housing part.
It is an object of the present invention to simplify and render less expensive the releasable fastening of a removable frame to the housing part of a dry shaving apparatus of the type initially referred to, while ensuring a vibration-free fastening of the removable frame to the housing part.
According to the present invention, this object is accomplished in a dry shaving apparatus.
It is an essential advantage of the present invention that the existing detent devices releasably holding the removable frame on the housing part are utilized for a reliable, vibration-free seat of the removable frame on the housing part, thereby eliminating the need for additional, cost-producing components.
In a preferred embodiment of the invention the locking force of the detent element is convertible into a position-force component and a holding-force component by spatially aligning the seating surfaces of the detent element and the seating surfaces of the removable frame. In a further aspect of this embodiment, the vibration-free positioning of the removable frame is determined by engagement of the removable frame with a stop on the housing part under the action of the position-force component upon the seating surface of the removable frame. The significant advantage of these arrangements resides in that, proceeding from the known state of the artxe2x80x94see DE 196 32 333 C1xe2x80x94it is only necessary for the existing seating surfaces on the detent elements and for the seating surfaces provided in the removable frame to be given a different shape, such that the spatial alignment of all seating surfaces effects a conversion of the locking force of the detent element into a holding-force component and a position-force component pointing in a common direction. This is purely a matter of shape design accomplishable simply by modifying the injection molds for the detent elements and the removable frame.
In a preferred embodiment of the invention, the stop is formed by an inner surface of the housing part. This embodiment, for example, incurs no cost because an existing wall of the housing part is made use of as seat or support of the removable frame for vibration-free seating. Any wear occurring on the seating surfaces of the detent elements and the seating surfaces in the removable frame and also on the cooperating surfaces of the removable frame and the stop are compensated for automatically through the locking force of the detent elements.
In a further aspect of the invention the stop is provided on an inner surface of the housing part. In a further aspect of the invention the inner surface is a component part of an end wall of the housing part. An essential advantage of these embodiments is that they equally make use of existing components, such as the end wall of the housing part, to perform a further new function.
A preferred embodiment of the invention is characterized in that the position-force component is effective only in one direction of the directions of oscillation of the movable cutter element. This has the advantage that by virtue of a corresponding contour of the seating surfaces on the detent elements the removable frame is seatable on and lockable with the housing part either way.
In an embodiment of the invention the holding-force component is effective in opposition to the direction of withdrawal of the removable frame from the housing part.
In a preferred embodiment of the invention two seating surfaces are provided on each longitudinal side wall of the removable frame.
A particularly advantageous embodiment of the invention is characterized in that, proceeding from a common origin the seating surfaces extend at an inclination to the x-axis, the y-axis and the z-axis. In a preferred embodiment of the invention, with reference to the stop all the seating surfaces provided on the longitudinal side walls of the removable frame are constructed to ascend in the coordinate axes x and y as well as x and z relative to a common origin. In adaptation to these embodiments, in a further aspect of the invention at least one seating surface is provided on the detent element. In a preferred embodiment of the invention, two seating surfaces are provided on the detent element. In a further aspect of this last-mentioned embodiment, the seating surfaces are constructed so as to extend in wedge shape relative to each other. A significant advantage of this embodiment resides in that it eliminates the need for the removable frame to be installed in a particular seating direction when it is placed down on the housing part and locked therewith by means of the detent elements for it to be subsequently held against the stop provided on the housing part in vibration-free manner.
In another embodiment of the invention the alignment of the seating surfaces of the detent elements is adapted essentially to the alignment of the seating surfaces on the removable frame. In a further aspect of this embodiment, the shape of the seating surface of the detent element is adapted to the seating surface of the removable frame in such manner that the engagement of cooperating seating surfaces is determined by line-type contact. An alternative embodiment of the invention is characterized in that the engagement of the seating surface of the detent element with the seating surfaces of the removable frame is determined by point-type contact.
In a still further embodiment of the invention the detent elements arranged in the housing part are adapted to be acted upon by a spring element. Preferably, a spring element is provided to act upon two detent elements acting in opposite directions.
Embodiments of the present invention will be illustrated and described in more detail in the following with reference to the accompanying drawings.